Metallurgical investigations of dry sliding surface layers in phosphorus iron/steel friction pairs

Wear ◽  
2002 ◽  
Vol 252 (3-4) ◽  
pp. 269-275
Author(s):  
Y.Z Zhang ◽  
S.J Wu ◽  
W.M Liu ◽  
Y Chen ◽  
B Shang Guan ◽  
...  
Keyword(s):  
Dry Sliding ◽  
Sliding Surface ◽  
Surface Layers ◽  
Phosphorus Iron

scholarly journals CHARACTERISTICS OF DRY SLIDING ELECTRIC CONTACT OF METALS IN CONDITIONS OF CATASTROPHIC WEARING

2019 ◽  
Vol 62 (2) ◽  
pp. 103-108 ◽  
Author(s):  
M. I. Aleutdinova ◽  
V. V. Fadin
Keyword(s):  
Current Density ◽  
Niti Alloy ◽  
Wear Intensity ◽  
Contact Temperature ◽  
Structural Defects ◽  
Dry Sliding ◽  
Sliding Surface ◽  
Surface Layers ◽  
Strong Adhesion ◽  
Steel 1020

The authors have studied the relation between wear intensity, average contact temperature and phase composition of the surface layers ofAISI 1020 steel, copper and NiTi alloy in dry sliding against the steel counterbody under electric current of density higher than 100  A/cm2 . These contact characteristics are considered carefully at the beginning of catastrophic wear, when the surface layers transit to the utmost state. It was noted that relaxation of stresses in the surface layers was due to the structural transformation in normal wear regime. It leads to tribolayers formation. The high strength of the copper tribolayer is first of all due to the formation of FeO oxide on the sliding surface, which prevents adhesion in contact. In addition, signs of a  liquid phase were observed on the copper contact surface. It promoted the low rate of formation and accumulation of structural defects. Emergence of areas of melt and FeO oxide on the sliding surface provides high contact wear resistance. These factors, combined with the high thermal copper conductivity, have caused the tribolayer transition to the limit state at high current density and low contact temperature. The absence of oxides on the sliding surface of the NiTi alloy has caused strong adhesion in the contact, high rate of formation and accumulation of structural defects. Therefore, the tribolayer quickly deteriorates and high wear intensity and rapid increase in the contact temperature are observed with current density increase. Therefore, the catastrophic wear of the NiTi alloy begins at a temperature about 350  °C and at low current density. The sliding surface of AISI 1020 steel contained FeO oxide, therefore strong adhesion is not manifested. Formation of FCC-Fe in tribolayer of AISI steel 1020 is detected, that promotes its accelerated deterioration. Therefore, the tribolayer of AISI steel  1020 transites to the utmost state at a relatively low current density and at a  higher temperature. The presented contact temperatures corresponding to the beginning stages of the utmost state of the tribolayer do not exceed 350  °С. Comparison of these temperatures with the known contact temperatures of other metals made it possible to assert that raising of the contact temperature of any metal higher than 400  °С leads to its utmost state. Therefore the characteristics of metals contact at temperatures of sliding contact higher than 500  °С is not of practical interest.

Interaction of tungsten in dry sliding against steel under high density electric current

2019 ◽  
pp. 101-109 ◽  
Author(s):  
M. I. Aleutdinova ◽  
V. V. Fadin ◽  
Yu. P. Mironov
Keyword(s):  
Electrical Contact ◽  
Analysis Data ◽  
Dry Sliding ◽  
Sliding Surface ◽  
X Ray ◽  
Sliding Surfaces ◽  
Quenched Steel ◽  
Sliding Electrical Contact ◽  
A Current ◽  
Tungsten Steel

The possibility of creating a wear-resistant dry sliding electrical contact tungsten/steel was studied. It was shown that tungsten caused severe wear of the quenched steel counterbody due to unlimited plastic flow of its surface layer at a current density up to 150 A/cm2 . This indicated the impossibility of achieving satisfactory characteristics of such a contact. Low electrical conductivity and wear resistance of the contact tungsten/steel were presented in comparison with the known high copper/steel contact characteristics under the same conditions. X-ray phase analysis data of the steel sliding surfaces made it possible to state that the cause of the unsatisfactory sliding of tungsten was the absence of the necessary concentration of FeO oxide on the sliding surface of the steel. 

scholarly journals Deterioration of surface layers of tungsten and steel-containing materials in current collection sliding against molybdenum

2021 ◽  
Vol 64 (2) ◽  
pp. 122-128
Author(s):  
M. I. Aleutdinova ◽  
V. V. Fadin
Keyword(s):  
Electrical Conductivity ◽  
Iron Oxides ◽  
Electrical Contact ◽  
Bearing Steel ◽  
Wear Intensity ◽  
Oxide Content ◽  
Molybdenum Oxides ◽  
Sliding Surface ◽  
Surface Layers ◽  
Current Collection

The possibility of improving the characteristics of a dry sliding electrical contact with a current density higher than 100 A/cm2 by using a molybdenum counterbody is considered. It is shown that tungsten or metallic materials containing bearing steel (1.5 % Cr) in sliding against molybdenum at a speed of 5 m/s under electric current, forms a contact with low electrical conductivity and high wear intensity. This observation served as the basis of this work. Using optical and electron microscopy of sliding surfaces it was found that strong adhesion in the interface was the main reason for rapid surface layers deterioration and high wear intensity. A well-known statement was taken into account that adhesion is due to the low oxide content between the contact surfaces. Visual study of molybdenum sliding surface made it possible to establish formation of a thin transfer layer and absence of traces of oxide formation. The same was observed on sliding surface of tungsten that was caused by high temperature of tungsten and molybdenum oxides formation. A layer of iron oxides was observed on sliding surface of steel containing materials. In addition, traces of a thin tribolayer were find out. An increase in concentration of steel in the primary structure led to a slight increase in iron oxides on the sliding surface, but did not lead to a significant increase in electrical conductivity and wear resistance of the contact. Unsatisfactory characteristics of the contact allowed us to conclude that it is impossible to significantly improve sliding parameters with current collection against molybdenum and inappropriateness of its use as a counterbody for these conditions.

On self-organization of the surface layer of structural steel in dry sliding against quenched steel under electric current

2021 ◽  
pp. 29-37
Author(s):  
M. I. Aleutdinova
Keyword(s):  
Structural Steel ◽  
Electric Current ◽  
Hardened Steel ◽  
Self Organization ◽  
Confocal Laser ◽  
Dry Sliding ◽  
Surface Layers ◽  
X Ray ◽  
Quenched Steel ◽  
Two Sectors

Using optical and confocal laser microscopes it was shown that dry sliding of structural steel against hardened steel under electric current of density higher 250 A/cm2 was accompanied by the formation of composite tribolayers. By X-ray phase analysis of the surface layers of the sample and counterbody was shown that they contain α-Fe, γ-Fe, and FeO. It is noted that the self-organization of the tribosystem under conditions of dry sliding under electric current can be represented as a hierarchy of structural states of the surface layers of contacting materials. It was found that the nominal sample area had two sectors. The character of the contact interaction in the sectors differs from each other.

Structure and Worn Surface Morphology on Copper Containing Composites under Dry Sliding with High Contact Current Density

2016 ◽  
Vol 712 ◽  
pp. 137-142
Author(s):  
Viktor V. Fadin ◽  
Marina I. Aleutdinova ◽  
Valery E. Rubtsov ◽  
Valeriya A. Aleutdinova
Keyword(s):  
Surface Layer ◽  
Liquid Phase ◽  
Surface Morphology ◽  
Current Density ◽  
Wear Intensity ◽  
Dry Sliding ◽  
Sliding Surface ◽  
Worn Surface

Dry sliding of the sintered composites of compositions Cu-graphite-Fe and Cu-Fe against steel at the contact current density higher 100 A/cm2 has been carried out. The presence of FeO oxide in surface layer was shown. The low content of FeO oxide resulted in high wear intensity. Formation of a liquid phase on a sliding surface was observed. Wear intensity was low in the presence of a liquid phase on the worn surface.

Frictional Temperature Field and Wear Behavior of Steel 52100 With Different Microstructures

1994 ◽  
Vol 116 (2) ◽  
pp. 255-259 ◽  
Author(s):  
You Wang ◽  
Mufu Yan ◽  
Xiaodong Li ◽  
Tingqun Lei
Keyword(s):  
Thermal Conductivity ◽  
Wear Resistance ◽  
Temperature Field ◽  
Wear Behavior ◽  
Temperature Fields ◽  
Wear Testing ◽  
Dry Sliding ◽  
Surface Layers ◽  
Close Relationship ◽  
Thermal Video

In this paper, the frictional temperature fields and the wear resistance of steel 52100 with different microstructures during dry sliding were studied by wear testing and computer simulation for thermometric data, which were real-time recorded by a thermal video system, using a mathematical model of frictional temperature field. The results show that the wear resistances of different microstructures are in close relationship with the temperature fields in surface layers during sliding. It is suggested that, because the different microstructures possess different thermal conductivities, the different microstructures will exhibit different frictional temperature fields, which will affect the wear resistances themselves. The less the thermal conductivity, the higher is the surface temperature during sliding, the lower is the wear resistance too.

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